Process for producing molded article of reclaimed thermoplastic resin

Abstract

The object of the present invention is to provide a recycled molded article, not having defects such as sink, warping, bending, and the like, and whose molding contraction does not change substantially depending on its recycle turn number so that said molded article having a good dimensional stability can be manufactured without changing design of the injection molding machine or molding conditions in every turn. To attain this object, the gas assist injection molding method or the expansion injection molding method wherein gas pressure or expansion pressure is effected on the melted molding material mixture in the mold, are applied in the present invention. By applying these methods, the melted molding material mixture may fill the mold uniformly and contraction strain by cooling may be absorbed in the inner hollow or the foamed structure in the resulting molded article, and further change of mold contraction depending on recycle turn number is reduced to obtain a molded article having a good dimension stability.

1 . A method for manufacturing a molded article comprising molding a recycled thermoplastic resin containing a recycle aid agent, or a mixture of said recycled thermoplastic resin, and virgin thermoplastic resin, said mixture containing said recycled thermoplastic resin in an amount of at least 1% by weight, or a mixture of said recycled thermoplastic resin and said virgin thermoplastic resin and said recycle aid agent, said mixture containing said recycled thermoplastic resin in an amount of at least 1% by weight for said virgin thermoplastic resin, by gas assist injection molding or expansion injection molding, wherein said recycled thermoplastic resin is recovered from discarded thermoplastic resin molded article.  
     
     
         2 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 1 , wherein said thermoplastic resin is styrenic resin.  
     
     
         3 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 1 , wherein said thermoplastic resin is olefinic resin.  
     
     
         4 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 1 , wherein said thermoplastic resin contains diene group rubber and/or olefinic rubber and/or acrylic rubber.  
     
     
         5 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 1 , wherein said recycle aid agent is a rubber like material having compatibility with said thermoplastic resin and said rubber like material is added to said thermoplastic resin in an amount of 1 to 5% by weight.  
     
     
         6 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 5 , wherein said thermoplastic resin is styrenic resin and said rubber like material as an recycle aid agent is a graft polymer in which diene group rubber and/or olefinic rubber and/or acrylic rubber is(are) a trunk and a polymer chain having compatibility with said styrenic resin is a grafted polymer chain.  
     
     
         7 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 5 , wherein said thermoplastic resin is olefinic resin and said rubber like material as an a recycle aid agent is ethylene-α-olefin copolymer.  
     
     
         8 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 1 , wherein paint or ink using thermoplastic resin having compatibility with said thermoplastic resin or thermosetting resin as a vehicle is applied to the surface of said molded article made of recycled thermoplastic resin.  
     
     
         9 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 8 , wherein non yellowing type cellulose derivative is added to said paint or said ink.  
     
     
         10 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 1 , wherein sheeting made of thermoplastic resin having compatibility with said thermoplastic resin of said molded article is stuck on the surface of said mold using adhesive made of thermoplastic resin having compatibility with said thermoplastic resin of said molded article of thermosetting resin.  
     
     
         11 . A method for manufacturing a molded article made of recycled thermoplastic resin in accordance with  claim 1 , wherein sheeting made of thermoplastic resin having compatibility with said thermoplastic resin of said molded article is stuck on the surface of said mold using adhesive made of thermoplastic resin having compatibility with said thermoplastic resin of said molded article or thermosetting resin.